MPC-OS is the Operating System of the MPC parallel computer.
It contains about 40000 lines of mixed C/C++/perl/shell/XWindow.
It runs on FreeBSD-2.1.0 to FreeBSD-2.2.5, FreeBSD-3.0 and FreeBSD-3.1.
Full documentation available here: http://fenyo.net/newweb/softsmpcos.html